Phase locking in a multi-channel quantum communication system
US7706536B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 2005 |
| Grant date | Apr 27, 2010 |
| Priority date | — |
| Expiry date | Feb 25, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L9/0858
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A communication system adapted to use wavelength (frequency) division multiplexing for quantum-key distribution (QKD) and having a transmitter coupled to a receiver via a transmission link. In one embodiment, the receiver is adapted to (i) phase-shift a local oscillator (LO) signal generated at the receiver, (ii) combine the LO signal with a quantum-information (QI) signal received via the transmission link from the transmitter to produce interference signals, (iii) measure an intensity difference for these interference signals, and (iv) phase-lock the LO signal to the QI signal based on the measurement result. In one configuration, the QI signal has a plurality of pilot frequency components, each carrying a training signal, and a plurality of QKD frequency components, each carrying quantum key data. Advantageously, the system can maintain a phase lock for the QKD frequency components of the QI and LO signals, while the QKD frequency components of the QI signal continuously carry quantum key data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.